Forget what you've been told about parking yourself cross-legged for twenty minutes and aiming for a "blank mind." That sentence alone was dreamed up by someone whose brain has only barely a few tabs running at once, ghost of yotei meditate.
The ADHD brain feeds on dopamine and novelty and and a stream of sensory information — so the opposite of those things (calm, hush, repetition) when requested of us, would in most people cause them to feel like something's wrong with them, like everyone else would — but also feel like a total failure. Which, again, does not ever come from willpower — it comes from improper usage. Two minutes is the target.
Don't reach for ten minutes.
Actually start trying for two; which, in the first 30 seconds of which, you are going to drift off in some kind of spectacular way anyway; so with all due respect, the less runway you have when it first bolts, the less time it has to get away from you,and you can bring it back! Success is simply coming back —and this is your entire rep. When doing the rep for 50 occasions throughout two minutes —you would most certainly generate more focus muscle than someone who just quietly sat for twenty minutes on the floor,totally unaware of everything.
Motion works greatly; a walking practice, free-form dancing, even wandering the house; or literally any physical activity while working on mindfulness... Anything! Try pacing the house or the room with something to hold or touch and just tune into your breath when it would not be a good situation at all,if anyone in the world were to observe your behavior! Whether you buy it or not... "clean the kitchen" meditation (the tap on, hands occupied and mind in its body) is frequently how the most present, intelligent minds actually find bliss with meditation instead of a perfectly poised, Instagram-worthy, meditative bliss pose.
Sound can be another lifesaver where true silence becomes almost unbearable in an ADHD brain. Play your favorite meditation recordings, background tones, or even just the tick of a clock in your room and your brain will do the rest by latching onto whatever thing it is listening to!
Timing of this meditation session during your day matters too... Should you have prescription medication that you take throughout the day then this is frequently a much better time than right when you wake up — when your brain is not exactly ready at all.